Which of these cars would i be better off buying, and what are the cons and pros of both?

Unless you are paying cash or have excellent credit you will not be able to finance BMW. You will also need money for expensive upkeep and insurance. The Caddy or Chevy is worth a lot more and will have better resale and less expensive repairs being a GM car and will be able to get financed easier. Banks will not finance 80K miles or over 8 years unless collectors car or you have near perfect credit for an unsecured loan.